Intracranial Stenosis Patients Research Articles

The Associations Between Intracranial Stenosis, Brain Amyloid-beta, and Cognition in a Memory Clinic Sample.

Intracranial stenosis (ICS) and brain amyloid-beta (Aβ) have been associated with cognition and dementia. We aimed to investigate the association between ICS and brain Aβ and their independent and joint associations with cognition. We conducted a cross-sectional study of 185 patients recruited from a memory clinic. ICS was measured on 3-dimensional time-of-flight magnetic resonance angiography and defined as stenosis ≥50%. Brain Aβ was measured with [ 11 C] Pittsburgh compound B-positron emission tomography imaging. Cognition was assessed with a locally validated neuropsychological battery. A total of 17 (9.2%) patients had ICS, and the mean standardized uptake value ratio was 1.4 (±0.4SD). ICS was not significantly associated with brain Aβ deposition. ICS was significantly associated with worse global cognition (β: -1.26, 95% CI: -2.25; -0.28, P =0.013), executive function (β: -1.04, 95% CI: -1.86; -0.22, P =0.015) and visuospatial function (β: -1.29, 95% CI: -2.30; -0.27, P =0.015). Moreover, in ICS patients without dementia (n=8), the presence of Aβ was associated with worse performance on visuomotor speed. ICS was significantly associated with worse cognition and showed interaction with brain Aβ such that patients with both pathologies performed worse on visuomotor speed specifically in those without dementia. Further studies may clarify if ICS and brain Aβ deposition indeed have a synergistic association with cognition.

Accuracy of transcranial Doppler in detecting intracranial stenosis in patients with sickle cell anemia when compared to magnetic resonance angiography.

Stroke, the most devastating consequence of sickle cell anemia (SCA), is associated with endothelial damage and intracranial artery stenosis. We aimed to assess transcranial Doppler (TCD) ultrasound accuracy in detecting intracranial stenosis when compared to magnetic resonance angiography (MRA). Children with SCA and at least one TCD and MRA within 1 month were identified from a retrospectively collected database. Sensitivity and specificity were obtained to assess the overall accuracy of TCD mean flow velocity (mFV) ≥200 cm/s in detecting vessel stenosis of ≥50%. Multivariate analysis identified independent factors associated with MRA stenosis. Among 157 patients in the database, 64 had a TCD and MRA within 1 month (age 11.8 ± 5.3 years, 56% female, 20% with cerebral infarcts on MRI, 8 or 13% had mFV ≥200 cm/s and 20% or 21%, had intracranial stenosis ≥50% on MRA). TCD mFV ≥200 cm/s had a high specificity (95%) but low sensitivity (29%) to detecting intracranial stenosis. As a continuous variable, TCD mFV of 137.5cm/s had maximal specificity (77%) and sensitivity (72%). After adjustment for age, hemoglobin level, transfusion status, hydroxyurea treatment, and vessel, for every increase in cm/sec on TCD, there was a 2% increase in the odds of ≥50% stenosis on MRA (p < 0.001). Our study reports TCD mFV is a positive predictor of MRA stenosis in SCA, independent of patient characteristics, including hemoglobin. A mFV ≥200 cm/s is highly specific but less sensitive in detecting stenosis ≥50%. Lower mFV cut points may be needed for the early detection of intracranial stenosis.

Abstract P582: Accuracy of Transcranial Doppler in Detection of Intracranial Stenosis in Patients With Sickle Cell Disease

Background: Stroke is among the most devastating consequences of sickle cell disease (SCD). Most SCD strokes occur due to intracranial stenosis, that can be detected by increased flow velocities on Transcranial Doppler (TCD). However, increased velocities may also reflect anemia rather than arteriopathy and vessel stenosis. We aimed to assess the accuracy of TCD in detection of intracranial stenosis in SCD. Methods: Pediatric SCD patients with at least one TCD and MRA within one month apart were identified from a retrospectively collected database maintained at our institution from January 2000 to December 2016. Patient demographics, hemoglobin level, transfusion and hydroxyurea status were collected, along with mean flow velocities (mFV) and degree of stenosis from bilateral middle and anterior cerebral, and internal carotid arteries. A mFV of &gt; 200 cm/s and vessel stenosis &gt; 50% were considered abnormal. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were obtained to assess overall accuracy of TCD velocities in relation to vessel stenosis. Multivariate analysis was performed to identify independent factors associated with MRA stenosis. Results: A total of 164 patients were included in the database (median age 12 [IQR 8.9] years, 56% had ischemic strokes) and 64 of them had at least one TCD and MRA one month apart. Of these, 20% had ischemic strokes, 17% had MRA stenosis &gt; 50% and 10% had TCD velocity &gt; 200 cm/s. TCD mFV &gt; 200 cm/s had a high specificity (95%) and NPV (87%) but low sensitivity (29%) and PPV (55%) when compared to MRA stenosis &gt; 50%. As a continuous variable, TCD mFV 137.5 cm/s had the best balance between maximal specificity (77%) and sensitivity (72%). After adjustment for age, hemoglobin level, transfusion status, hydroxyurea, and vessel, for every increase in cm/sec on TCD, there was a 2% increase in the odds of &gt; 50% stenosis on MRA (OR=1.02, 95% CI 1.01-1.03, p&lt;0.001). Conclusion: Our study reports that TCD mFV is a positive predictor of MRA stenosis in SCD, independent of patient characteristics, including hemoglobin. A mFV &gt; 200 cm/s is highly specific but less sensitive to detect stenosis &gt; 50%. Lower mFV cut points may need to be considered for early detection of intracranial stenosis and risk of stroke.

Prognosis of Asymptomatic Intracranial Stenosis in Patients With Transient Ischemic Attack and Minor Stroke

Asymptomatic intracranial stenosis (ICS) is a frequent finding on imaging results, particularly in the assessment of acute stroke. Although the management of symptomatic ICS is informed by randomized trials, to our knowledge there are few data on the prevalence and prognosis of asymptomatic ICS in patients with stroke and transient ischemic attack (TIA). To study the age-specific prevalence and prognosis of asymptomatic ICS in a population-based cohort of patients with TIA and minor stroke. All patients (predominantly white) recruited to the Oxford Vascular Study (Oxfordshire, England) between March 1, 2011, and March 1, 2018, with TIA and minor ischemic stroke (National Institutes of Health Stroke Scale score, ≤3), irrespective of age, were included (n = 1579). We determined the age-specific prevalence of 50% or more asymptomatic ICS and the associated stroke risk by face-to-face follow-up to 2018 on standard medical treatment without stenting. Patients underwent magnetic resonance angiography of the intracranial and cervicocranial arteries, computed tomography angiography if magnetic resonance angiography was contraindicated, or carotid/transcranial Doppler ultrasonography if computed tomography angiography was contraindicated. The primary outcomes were the prevalence and prognosis of asymptomatic ICS. Of 1368 eligible patients (mean [SD] age, 69.2 [13.9] years; 700 men [51.2%]) with intracranial vascular imaging, 426 ICS were identified in 260 patients (19.0%): 58 (4.2%) with only symptomatic ICS, 155 (11.3%) with only asymptomatic ICS, and 47 (3.4%) with both. The prevalence of any asymptomatic ICS increased from 4.8% for patients younger than 70 years to 34.6% for patients 90 years or older (P for trend < .001; odds ratio per decade, 1.96; 95% CI, 1.69-2.27) and was greater than that of 50% or more asymptomatic carotid bifurcation stenosis (202 [14.8%] vs 105 patients [7.2%]; relative risk, 2.04; 95% CI, 1.63-2.55, P < .001). However, the 155 patients with only asymptomatic ICS had no increase in risk of ischemic stroke compared with those with no ICS (unadjusted HR, 1.03, 95% CI, 0.49-2.17), with 8 first recurrent events (5.2%) during 506 patient-years of follow-up and 3 in the territory of the ICS (annualized risk, 0.59%; 95% CI, 0.12-1.73). The prevalence of asymptomatic ICS increases with age in white patients with TIA and minor stroke and is greater than that of asymptomatic carotid stenosis, but asymptomatic ICS does not increase the short- or medium-term risk of distal recurrent ischemic stroke for patients receiving standard medical treatment.

Prevalence, predictors, and prognosis of symptomatic intracranial stenosis in patients with transient ischaemic attack or minor stroke: a population-based cohort study.

SummaryBackgroundSymptomatic intracranial stenosis was perceived to convey a high risk of recurrent stroke, but two previous trials (SAMMPRIS and VISSIT) did not show superiority of intracranial stenosis stenting over intensive medical management alone. These findings were partly due to a lower than expected risk of recurrent stroke without stenting, possibly reflecting the young age of recruits (median age <60 years), and raise questions about generalisability to routine clinical practice. We therefore studied the age-specific prevalence, predictors, and prognosis of symptomatic intracranial stenosis in a population-based cohort of patients with transient ischaemic attack and minor stroke on intensive medical management.MethodsThe Oxford Vascular Study (OXVASC) is a prospective incidence cohort study of all vascular events in a population of 92 728 people residing in Oxfordshire, UK. All patients, irrespective of age, with transient ischaemic attack and minor ischaemic stroke occurring between March 1, 2011, and March 1, 2018 (follow-up to Sept 28, 2018), were ascertained with multiple methods, including assessment in a dedicated daily emergency clinic and daily review of all hospital admissions. Imaging was by MR angiography of the intracranial and cervicocranial arteries, by CT angiography if MR angiography was contraindicated, and by transcranial Doppler and carotid ultrasound if CT angiography was contraindicated. All patients received intensive medical treatment without stenting, and those with intracranial vascular imaging were analysed in our study, which assessed the age-specific prevalence of 50–99% intracranial stenosis and the associated stroke risk of 50–99% and 70–99% stenosis (adjusted for age and vascular risk factors) during follow-up to Sept 28, 2018.FindingsOf 1368 eligible patients with intracranial vascular imaging, 241 (17·6%) had 385 50–99% symptomatic or asymptomatic intracranial stenosis. The prevalence of symptomatic 50–99% intracranial stenosis increased from 29 (4·9%) of 596 at younger than 70 years to 10 (19·6%) of 51 at 90 years or older (ptrend<0·0001). Of 94 patients with 50–99% symptomatic intracranial stenosis, 14 (14·9%) had recurrent strokes (12 ischaemic and two haemorrhagic) during a median follow-up of 2·8 years (IQR 1·5–4·6). Although symptomatic intracranial stenosis conveyed an increased risk of ischaemic stroke compared with no intracranial stenosis (adjusted hazard ratio 1·43, 95% CI 1·04–1·96), the risk of same-territory ischaemic stroke in patients with 70–99% symptomatic intracranial stenosis tended to be less than those reported in the non-stenting groups of the previous trials (1-year risk 5·6% [95% CI 0·0–13·0] vs 9·4% [3·1–20·7] in VISSIT; 2-year risk 5·6% [0·0–13·0] vs 14·1% [10·1–19·4] in SAMMPRIS).InterpretationThe prevalence of 50–99% symptomatic intracranial stenosis increases steeply with age in predominantly Caucasian patients with transient ischaemic attack and minor ischaemic stroke. However, the risk of recurrent stroke on intensive medical treatment of symptomatic intracranial stenosis is consistent with the two previous randomised controlled trials in younger cohorts, supporting the generalisability of the trial results to routine practice.FundingWellcome Trust, Wolfson Foundation, British Heart Foundation, National Institute for Health Research, National Institute for Health Research Oxford Biomedical Research Centre, Association of British Neurologists.

Prevalence, Predictors, and Prognosis of Intracranial Stenosis in Patients with TIA and Minor Stroke: Population-based Study Versus Randomized Trials (1766)

Prevalence, Predictors, and Prognosis of Intracranial Stenosis in Patients with TIA and Minor Stroke: Population-based Study Versus Randomized Trials (1766)

Color-coded duplex sonography vs. 3.0 Tesla magnetic resonance angiography for detection of intracranial stenosis of the internal carotid artery: A prospective cohort study.

Hemodynamic changes may provide important information for clinical decision-making in internal carotid artery (ICA) stenosis. The degree of stenosis is responsible for the hemodynamic changes. For detection of intracranial stenosis, each diagnostic method has its own advantages and disadvantages. The goal of the present study was to compare the sensitivity and accuracy of color-coded duplex sonography with that of magnetic resonance angiography (MRA) for the detection of intracranial stenosis. Patients with 3 vessels and/or left stem coronary artery disease were subjected to transcranial and extracranial color-coded duplex sonography (n=998), MRA (n=998) and invasive catheter angiography (n=939). The degree of stenosis was defined according to the Warfarin-Aspirin Symptomatic Intracranial Disease methodology. A ≥50% reduction in artery diameter was considered as a positive obstructive lesion. The benefits of each imaging method were assessed by clinical decision-making analysis. Color-coded duplex sonography and MRA, had sensitivities of 0.935 and 0.957 and accuracies of 0.92 and 0.974, respectively, when using invasive catheter angiography as a gold standard. The number of false-positive obstructive lesions detected by MRA was significantly higher than that for color-coded duplex sonography (53 vs. 13, P<0.0001). Color-coded duplex sonography was able to detect an obstructive lesion in one single image for ICAs with ≥57% stenosis, while MRA was only capable of detecting an obstructive lesion in one single image for ICAs with ≥80% stenosis. In conclusion, color-coded duplex sonography is a reliable method for the detection of intracranial stenosis in patients with coronary artery disease.

Abstract TP527: Baseline Physical Activity Profiles in CREST-2 Trial Participants

Background: The importance of physical activity in preventing major vascular events has received increased attention in the past decade. Due to the inclusion of the INTERVENT lifestyle modification program, the CREST2 trial provides a unique opportunity to study physical activity profiles in patients with severe asymptomatic extracranial carotid stenosis. Hypothesis: Based on data from a trial of intracranial stenosis patients, we aimed to evaluate the hypothesis that &lt;40% of carotid stenosis subjects will have optimal physical activity levels. We also assessed key subgroups to determine patterns of physical activity. Methods: We analyzed 1087 CREST2 participants with baseline data on physical activity. The Physician-based Assessment and Counseling for Exercise (PACE) score is recorded for each patient and dichotomized as “in target” (4-8 points) or “out of target” (&lt;4 points). A PACE score of &lt;4 indicates a subject who does not engage in regular exercise. Results are analyzed for the entire trial. Chi square testing and t-tests were performed for evaluation of subgroup differences. Results: The mean age of the study population is 69.5±7.8 years (60% male). The median PACE score at baseline is 4.0 (mean 3.8±2.1; IQR 2 to 6). The Table shows baseline characteristics of patients by mean PACE score. Being male, not having diabetes mellitus, having a body mass index &lt;30kg/m2, being a non-smoker, and not having a history of peripheral arterial disease were associated with significantly higher mean PACE scores (P&lt;0.01). Conclusions: We have defined several patient groups with asymptomatic carotid stenosis that have suboptimal physical activity. These results provide opportunities for targeted efforts to improve primary stroke prevention. These baseline data will also allow investigators to determine if trial involvement and the INTERVENT program leads to improvement in the level of physical activity.

A High Prevalence of Intracranial Stenosis in Patients with Coronary Artery Disease and the Diagnostic Value of Transcranial Duplex Sonography

Background: According to the data from the population-based Rotterdam study, intracranial carotid artery calcification detected by computed tomography is very common and contributed to 75% of all strokes. The aim of the present study was to estimate the prevalence of intracranial stenosis (IS) using noninvasive transcranial color-coded duplex sonography (TCCS) in neurologically asymptomatic patients with coronary artery disease (CAD). Methods: Three hundred and eighty-nine patients with angiographically-confirmed, severe CAD were included prospectively. All of them were examined using extracranial and TCCS. Results: Out of 389 patients (age 66.7 ± 9.2, 39-88), 237 (61%) were diagnosed with 3 vessels disease and 152 patients (39%) with left stem disease with/without 3 vessels damage. Transcranial sonography revealed at least 1 IS in 63.6% of echo positive patients (220/346). IS was found in 127 (61.4%) patients with 3 vessels disease, 20 patients (58.8%) with isolated left stem disease, and 73 patients (69.5%) with 3 vessels and left stem disease (P = .305). In the case of significant (≥50%) extracranial internal carotid artery stenosis, intracranial stenosis were detected in 84.8% (50 of 59), in the case of mild (<50%) stenosis, in 59.2% (170 of 287), P < .001. Conclusions: It was found that two thirds of patients with advanced CAD have a silent IS. TCCS is a reliable method for the evaluation of intracranial atherosclerosis in such patients in order to gain useful information about cerebrovascular disease as a risk factor for stroke.

The prevalence of intracranial stenosis in patients at low and moderate risk of stroke.

Background:Previous studies assessing the risk of stroke in the general population performed screening with Doppler ultrasonography only for high-risk patients and neglected low- and moderate-risk patients. The aims of this study were to explore the current prevalence of intracranial arterial stenosis (ICAS) and analyze its association with different levels of stroke risk and risk factors based on the risk assessment scale for stroke used in China.Methods:A total of 3654 participants who underwent transcranial Doppler ultrasound (TCD) were eligible for inclusion. Information regarding demographic characteristics and risk factors such as alcohol consumption and hypertension was collected through interviews and questionnaires and used to analyze the association of ICAS with different levels of stroke risk and risk factors.Results:The mean age of 501 subjects diagnosed with at least one ICAS was higher than that of participants without ICAS (57.13 ± 9.56 years and 55.52 ± 9.35 years, respectively). After adjusting for confounding factors, gender, education, residence, hypertension and personal history of stroke were associated with ICAS. The odds ratios for ICAS in patients with hypertension and a personal history of stroke were 1.655 [95% confidence interval (CI): 1.341–2.043] and 1.854 (95% CI: 1.371–2.508), respectively. In addition, participants in the low- and moderate-risk stroke groups accounted for an unexpectedly high proportion of individuals with ICAS (up to 38.3%). Results from multivariate analyses indicated that the adjusted odds ratios for ICAS in patients with moderate and high stroke risks versus those with a low stroke risk were 1.603 (95% CI: 1.171–2.195) and 1.612 (95% CI: 1.272–2.042), respectively.Conclusion:The prevalence of ICAS is high in northeast China and increases with the level of stroke risk. However, the proportion of patients with ICAS among those with low and moderate stroke risks should also be noted.

Abstract 62: Evaluating Collateral Flow Territory Stability As A Novel Biomarker Of Recurrent Stroke In Patients With Symptomatic Intracranial Stenosis

Introduction: Intracranial (IC) collateral pathways provide important indicators of arterial steno-occlusion compensation, however evaluating the adequacy of these pathways is difficult with existing methods. Here, we modulated arterial partial pressure of CO 2 with mild hypercapnic respiratory stimuli to evaluate the stability of cerebral blood flow (CBF) territories in IC stenosis patients as a novel marker of collateralization adequacy. Methods: Symptomatic IC stenosis (n=20) and healthy (n=10) volunteers provided written consent and underwent noninvasive vessel-encoded arterial spin labeling. Separate magnetic labeling of the left ICA, right ICA, and vertebral arteries was performed, yielding 3 CBF territories. Scans were performed during normocapnia and hypercapnia (5% CO 2 ) and patients were monitored for recurrent stroke for a mean 1.6 years. The primary study variable was the CBF territory shifting index, defined as the percent of voxels changing from normocapnia to hypercapnia; the clinical endpoint was new non-cardioembolic stroke, TIA, or silent cerebral infarct. Significance was defined as two-sided p&lt;0.05. Results: 10/20 patients experienced a clinical endpoint at or before follow-up. Shifting indices were significantly larger in patients meeting the clinical end-point (1.49±0.32) compared to controls (0.67±0.071; p&lt;0.022) and patients not meeting the endpoint (0.67±0.12; p&lt;0.0089) ( Fig. 1) . Using 1 standard error above the mean patient shifting index as a threshold, sensitivities and specificities for predicting the clinical endpoint were 70% (7 of 10) and 97% (29 of 30), respectively. Conclusion: Mild shifting of major CBF territories during hypercapnia may be elevated in IC stenosis patients at risk for recurrent stroke. This approach may provide a new marker of collateralization adequacy and risk of recurrent ischemic events. Figure 1: A. CBF territory shifting in a patient with left ICA stenosis. B. Boxplots of shifting indices.

Incidence and Clinical Significance of Acute Reocclusion after Emergent Angioplasty or Stenting for Underlying Intracranial Stenosis in Patients with Acute Stroke.

A major concern after emergent intracranial angioplasty in cases of acute stroke with underlying intracranial stenosis is the acute reocclusion of the treated arteries. This study reports the incidence and clinical outcomes of acute reocclusion of arteries following emergent intracranial angioplasty with or without stent placement for the management of patients with acute stroke with underlying intracranial atherosclerotic stenosis. Forty-six patients with acute stroke received emergent intracranial angioplasty with or without stent placement for intracranial atherosclerotic stenosis and underwent follow-up head CTA. Acute reocclusion was defined as "hypoattenuation" within an arterial segment with discrete discontinuation of the arterial contrast column, both proximal and distal to the hypoattenuated lesion, on CTA performed before discharge. Angioplasty was defined as "suboptimal" if a residual stenosis of ≥50% was detected on the postprocedural angiography. Clinical and radiologic data of patients with and without reocclusion were compared. Of the 46 patients, 29 and 17 underwent angioplasty with and without stent placement, respectively. Acute reocclusion was observed in 6 patients (13%) and was more frequent among those with suboptimal angioplasty than among those without it (71.4% versus 2.6%, P < .001). The relative risk of acute reocclusion in patients with suboptimal angioplasty was 27.857 (95% confidence interval, 3.806-203.911). Furthermore, a good outcome was significantly less frequent in patients with acute reocclusion than in those without it (16.7% versus 67.5%, P = .028). Acute reocclusion of treated arteries was common after emergent intracranial angioplasty with or without stent placement in patients with acute stroke with intracranial atherosclerotic stenosis and was associated with a poor outcome. Suboptimal results of angioplasty appear to be associated with acute reocclusion, irrespective of whether stent placement was performed.

Abstract TP213: Accuracy of Transcranial Color-coded Sonography for the Detection and Measurement of Intracranial Arterial Stenosis When Compared to CT Angiography in Patients With Acute Ischemic Stroke and Transient Ischemic Attack

Introduction: Transcranial Color-Coded Sonography (TCCS) including B-mode imaging and color-coded Duplex is non-invasive, bedside and inexpensive tool for the assessment of the intracranial circulation. TCCS can be used to assess intracranial stenosis but its accuracy has not been systematically compared to CT angiography in acute stroke patients. Hypothesis: TCCS has high accuracy when compared to CT angiography for the detection and measurement of intracranial arterial stenosis in patients with acute ischemic stroke. Methods: In this prospective study 43 patients (67% male; mean age: 59.8 ± 11 years) with acute ischemic stroke or Transient Ischemic Accident (TIA) underwent examinations of the intracranial arteries by TCCS and CT angiography. Different examiners that were blinded to test results performed the exams. TCCS and CT angiography were performed during the hospital stay. All stenotic segments of intracranial vessels were classified into 4 groups: normal or mild (&lt;50%), moderate (50%-70%), severe (≥70%) and subocclusion/occlusion. Results: 580 of 645 arterial segments in 43 patients were evaluated. The sensitivity, specificity, positive predictive value, and negative predictive value of TCCD in comparison with CT angiography for the detection of moderate to severe intracranial stenosis (≥50%) were 81.5%, 100%, 100%, and 76% respectively. The Cohen’s kappa between TCCS and CT angiography was 0.76 (p&lt;0.001). Conclusions: TCCS is a bedside non-invasive tool that can be used to evaluate intracranial arteries with high accuracy for moderate to severe stenosis when compared to CT angiography. Moderate agreement was found between TCCS and CT angiography for the evaluation of intracranial stenosis in patients with acute ischemic stroke or TIA.

Endovascular treatment and the outcomes of atherosclerotic intracranial stenosis in patients with hyperacute stroke.

The importance of underlying atherosclerotic intracranial artery stenosis (ICAS) in hyperacute stroke patients who receive endovascular therapy remains unknown. To report and compare the outcomes of multimodal endovascular therapy in patients with hyperacute stroke with and without underlying ICAS. A total of 172 consecutive patients with acute stroke were treated with multimodal endovascular therapy that was heavily weighted toward stent-based thrombectomy. Patients with ICAS underwent emergent intracranial angioplasty or stenting. Data were compared between patients with and without ICAS. Revascularization was defined as Thrombolysis in Cerebral Infarction grade ≥2b. A favorable outcome was defined as a modified Rankin Scale score ≤2 or equal to the premorbid modified Rankin Scale score at 3 months. ICAS was responsible for acute ischemic symptoms in 40 patients (22.9%). Revascularization and favorable outcome occurred more frequently in the ICAS group than in the control group (95% vs 81.8%, P = .04; 65% vs 40.2%, P = .01, respectively). The median baseline National Institutes of Health Stroke Scale score was significantly lower in the ICAS group compared with the control group (10 vs 12; P = .002). There were no significant differences between the 2 groups in the rates of symptomatic hemorrhage and mortality. Emergent intracranial angioplasty with or without stenting is safe and feasible and yields a high rate of revascularization and favorable outcome in patients with hyperacute stroke and underlying ICAS. Patients with underlying ICAS have less severe infarctions at presentation and higher successful revascularization after multimodal endovascular therapy in the setting of hyperacute stroke compared with those with other stroke subtypes.

Abstract 175: Vessel Wall Imaging at 3-Tesla in Patients with Symptomatic Intracranial Stenosis and Age-Matched Healthy Controls

Purpose: To translate a recently-proposed ultra-high field (7 Tesla) MRI protocol for assessing intracranial (IC) vessel wall morphology to the clinically available field strength of 3T to enable vessel wall imaging (VWI) routinely without contrast agent administration. Methods: Following protocol development, IC stenosis patients (n=16) and healthy volunteers (n=16) provided informed, written consent and underwent FLAIR, angiography, and a custom VWI protocol (3D turbo spin echo, TR=1500 ms; spatial resolution=0.5 mm isotropic, and anti-driven +90 equilibrium pulse). A board-certified neuroradiologist, blinded to clinical history, reviewed all images. Results: Vessel wall abnormalities were detected in all (12/16) participants with significant (&gt;50%) flow-limiting stenosis on angiography. Fig. 1 demonstrates changes for two individuals with VWI lesions. Two participants had advanced moyamoya disease and extensive collateralization on DSA, both of whom had corresponding findings on VWI. Fig. 1: IC stenosis visualized by VWI and DSA. A) 57 yr/M with flow-limiting basilar artery stenosis. VWI (left) in the coronal plane shows hyperintense signal of a vessel wall lesion in the basilar artery (red arrow). AP projection from the left vertebral injection during DSA (right) shows stenosis in the same region (red arrow). B) 53 yr/M following L MCA territory stroke. VWI (left) demonstrates wall thickening (red arrow) of left distal ICA continuous in the left proximal MCA which corresponds to stenosis on DSA (right, AP view from L ICA injection). Discussion: We show that it is possible to perform VWI without contrast at 3T and still retain an acceptable image quality for discerning IC vessel abnormalities. Cerebrovascular reactivity (CVR) data were also acquired in all patients as part of an ongoing IC stenosis clinical trial; parallel work is focused on characterizing relationships between vessel wall disease and parenchymal reactivity.

Routine clinical evaluation of cerebrovascular reserve capacity using carbogen in patients with intracranial stenosis.

A promising method for identifying hemodynamic impairment that may serve as a biomarker for stroke risk in patients with intracranial stenosis is cerebrovascular reactivity (CVR) mapping using noninvasive MRI. Here, abilities to measure CVR safely in the clinic using hypercarbic hyperoxic (carbogen) gas challenges, which increase oxygen delivery to tissue, are investigated. In sequence with structural and angiographic imaging, blood oxygenation level-dependent carbogen-induced CVR scans were performed in patients with symptomatic intracranial stenosis (n=92) and control (n=10) volunteers, with a subgroup of patients (n=57) undergoing cerebral blood flow-weighted pseudocontinuous arterial spin labeling CVR. Subjects were stratified for 4 substudies to evaluate relationships between (1) carbogen and hypercarbic normoxic CVR in healthy tissue (n=10), (2) carbogen cerebral blood flow CVR and blood oxygenation level-dependent CVR in intracranial stenosis patients (n=57), (3) carbogen CVR and clinical measures of disease in patients with asymmetrical intracranial atherosclerotic (n=31) and moyamoya (n=29) disease, and (4) the CVR scan and immediate and longer-term complications (n=92). Noninvasive blood oxygenation level-dependent carbogen-induced CVR values correlate with (1) lobar hypercarbic normoxic gas stimuli in healthy tissue (R=0.92; P<0.001), (2) carbogen-induced cerebral blood flow CVR in patients with intracranial stenosis (R=0.30-0.33; P<0.012), and (3) angiographic measures of disease severity both in atherosclerotic and moyamoya patients after appropriate processing. No immediate stroke-related complications were reported in response to carbogen administration; longer-term neurological events fell within the range for expected events in this patient population. Carbogen-induced CVR elicited no added adverse events and provided a surrogate marker of cerebrovascular reserve consistent with intracranial vasculopathy.

Abstract T P101: Low Serum Eicosapentaenoic Acid- Arachidonic Acid Ratio is Associated With Intracranial Stenosis in Patients With Acute Ischemic Stroke

Purpose: A low ratio of serum eicosapentaenoic acid to arachidonic acid (EPA/AA) has been associated with atherosclerotic disease. Few studies investigate the association of serum fatty acid (FA) composition with the acute ischemic stroke so far. Our aim of this study is to evaluate the relationships between FA composition and stroke subtypes, extra-/intracranial atherosclerotic stenoses, and other cerebrovascular indicators Methods: This study included 154 consecutive patients who were admitted to our hospital because of acute ischemic stroke between April 2011 and March 2012. We examined the FA composition and classical vascular risk factors. We conducted brain MRI/MRA, carotid ultrasonogram, transthoracic echocardiogram, 24hr Holter electrocardiogram, ankle brachial index (ABI) and pulse wave velocity (PWV) in order to evaluate the severity of atherosclerotic change, stroke subtype, and cardiovascular status. Results: The mean value of EPA/AA was 0.33±0.22 in all patients with acute cerebral infarction. The 154 patients in this study (mean age 71 years) were categorized as follows; large artery atherosclerosis (LA; n=57), small artery occlusion (SA; n=48), cardiogenic embolism (CE; n=18), and others (n=31). We found intracranial artery stenosis greater than 50% in 70 patients (45%). The intracranial artery stenosis was associated with low EPA/AA ratio (P=0.013) and low EPA concentration (P=0.013). This association remained significant (P&lt;0.05) after controlling for classical atherosclerotic risk factors. We could not find a significant correlation between FA composition and stroke subtype. However, there was a tendency for the EPA/AA ratio of LA patients to be the lowest among all subtype groups. The EPA/AA ratio was not associated with ABI, PWV, prevalence of arrhythmia, or cardiac function. Conclusions: A low EPA/AA ratio was significantly associated with intracranial stenosis in patients with acute ischemic stroke. This study shows the EPA/AA ratio might be an important marker to reflect the cerebral artery stenosis.

Abstract 167: Noninvasive MRI Measurement of Cerebrovascular Reactivity Enables Evaluation of Surgical Revascularization Response in Moyamoya

Introduction: Frequent dissociation between clinical severity and angiographic grading of moyamoya supports a role for alternative tissue-level hemodynamic measures. Here, angiography is complemented with noninvasive MRI measurements of parenchymal impairment to assess changes in cerebrovascular reactivity (CVR) after extracranial-intracranial bypass in moyamoya. Hypothesis: CVR is regionally impaired pre-operatively, yet increases after surgery. This can be visualized noninvasively by assessing blood oxygenation level-dependent (BOLD) MRI changes with safe, mildly hypercarbic gas. Methods: Using a block MRI paradigm, carbogen (5% CO 2 ; 95% O 2 3 min) was interleaved with atmospheric air (&lt;1% CO 2 ; 3 min) administration during BOLD MRI in intracranial stenosis patients (n=70), a subset of which (n=9; age=35.7+/-10.8; 7F/2M) underwent indirect (n=8) or direct (n=1) revascularization for moyamoya. Five patients had both pre-operative and post-operative hemodynamic imaging, with post-operative scans performed after 7.3+/-4.1 months. CVR, calculated as a z-statistic in response to hypercarbia vs. atmospheric air, was compared (two-tailed t-test) for each patient between the two time points to correlate CVR changes with surgery. Results: Fig. 1 shows BOLD MRI on a patient scanned before and 2 years after right-sided indirect bypass, with significant (t=79.29, p&lt;0.01) right-sided hemodynamic improvement. Cohort analyses of patients with pre/post-operative scans revealed significant interhemispheric CVR differences prior to surgery (t=3.48, p&lt;0.01), which resolved after bypass (t=0.88, p=0.20). Additionally, CVR increased significantly in the operative hemisphere (t=4.50, p&lt;0.01). Conclusions: CVR-weighted hemodynamic MRI can be implemented into routine clinical protocols, corresponds well with revascularization response, and has potential as a noninvasive complement to angiography for serial monitoring of moyamoya patients.

Abstract W P130: Relationship Between Risk Factor Control and Vascular Events in the Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) Trial

Background and Purpose: Symptomatic intracranial stenosis patients with poorly controlled cholesterol and blood pressure had an increased risk of vascular events in WASID. Therefore, SAMMPRIS aggressive medical management protocols targeted these risk factors. We sought to determine if intensive risk factor control in SAMMPRIS resulted in lower risk of vascular events during follow-up. Methods: Data on 227 SAMMPRIS patients randomized to aggressive medical management alone were used for these analyses. Vascular risk factors were recorded at baseline, 30 days, and every 4 months. Additional follow-up and close-out visit data were also included. For each patient, values for all risk factor measures (from baseline until the time of an event) were averaged and dichotomized based on the risk factor target. Time to event curves for a vascular event (stroke, MI, and vascular death) were compared between subjects with and without risk factor control using the log-rank test and hazard ratios were calculated with Cox proportional hazards regression. Results: The univariate analyses are shown in the table. Subjects with mean follow-up SBP &lt; 140 mm Hg (&lt; 130 for diabetics), LDL &lt; 70 mg/dL, and at least moderate exercise had lower risk of vascular events compared to those who did not achieve those targets. Control of other risk factors (HgA1c, smoking, non-HDL, and Body Mass Index) did not have a significant impact on outcome. Conclusions: Well controlled SBP and LDL during follow-up were predictors of lower vascular events in SAMMPRIS, confirming that SBP and LDL should be aggressively treated in patients with intracranial stenosis to prevent future vascular events. Exercise participation was also associated with fewer vascular events and should be strongly encouraged.

E-007 Urgent recanalization with stent for severe intracranial stenosis in patients with transient ischemic attack or minor stroke

Background and purposeStenting of symptomatic intracranial stenosis has recently become an alternative treatment modality. However, urgent intracranial stenting in patients with intracranial stenosis following a transient ischemic attack (TIA) or...